1. Field of the Invention
The present invention relates to an electronic device functioning as a telephone machine (telephone), and particularly to a portable information terminal. The present invention relates in particular to a portable information terminal having EL elements in a display portion. Note that, is in this specification, a portable information terminal denotes a communication device capable of being carried by a user and which possesses both a function of being able to exchange data with another individual while in motion, and a function as a telephone.
2. Description of the Related Art
Technology relating to flat panel displays has been developing rapidly in recent years under the background of increasing needs for lighter, thinner, and smaller displays. Flat panel displays are capable of displaying an image which is high quality, full color, and has high resolution. One type of flat panel display, liquid crystal display devices, are used in display portions of portable information terminals (such as a mobile computer, a portable telephone, a portable type game machine, and an electronic book).
FIG. 25 shows a portable telephone, which is one type of portable information terminal having a liquid crystal display device. The portable telephone shown in FIG. 25 includes a main body 2801, an audio output portion 2802, an audio input portion 2803, a display portion 2804, operation keys 2805, and an antenna 2806.
The portable telephone shown in FIG. 25 has a function as a telephone, namely it converts audio input to the audio input portion 2803 into electric waves and then outputs the electric waves, and it takes in electric waves having audio information to convert it to audio, then plays the audio in the audio output portion.
A liquid crystal display device is used in the display portion 2804, and is capable of displaying necessary information.
With the conventional portable information terminal shown in FIG. 25, images such as characters, numerals, or symbols are listed on or displayed on the operation keys so that the operator can recognize what type of information is input to the portable information terminal when which operation key is pressed. However, the direction of the characters, numerals, or symbols displayed on the operation keys is always fixed with a conventional portable information terminal. The operator therefore must use the portable information terminal by always aligning with the direction of the characters, numerals, or symbols displayed on the operation key, and the portable information terminal itself is not user friendly.